This invention relates generally to pumps and compressors, and more particularly, to electrically powered pumps and compressors of the reciprocating type.
Present day pumps and compressors are generally comprised of two basic types. These two basic types may be divided into rotary and reciprocating types. The rotary types comprise strictly rotary compressors such as gear pumps and impeller pumps, and the more common types wherein a crank shaft is employed to convert the rotary motion into reciprocating motion. The reciprocating types generally employ a linear motor having a two coil stator and an armature, and a pair of opposed pistons attached to the armature. The armature may be fabricated from a magnetic material, or may be a wire wound type. When a wire wound armature is used, the armature is engergized with alternating current, and when a magnetic armature is used, the stator coils ar alternately energized with direct current by means of a switch mechanically coupled to the armature.
While a large variety of pumps and compressors may be provided utilizing the conventional rotary and reciprocating techniques, pumps employing rotary techniques tend to have a large number of moving parts and hence, tend to be relatively costly and require periodic maintenance. Prior art pumps and compressors of the reciprocating type, while being less complex than rotary type pumps, tend to be inefficient in operation and limited in power.